The present invention relates to a control device in a mower which is driven by an engine.
In a conventional mower in which mowing is performed by a rotation of an engine, engine output is transmitted to a cutter blade through coupling of a clutch. During mowing, the engine is controlled to rotate at a constant rotation speed by means of a governor, etc., since generally no large load variation occurs during the mowing operation.
At the initial start-up period of the cutter blade, i.e. the time immediately after the coupling of the clutch, the engine rotation speed is generally lowered since the load applied to the engine is abruptly increased due to the inertial weight of the cutter blade.
Such abrupt lowering in engine speed due to such loa application to the engine is unfavorable for the engine per se, and further, an operator may occasionally have unsatisfactory feeling. Furthermore, there is a problem in that a relatively prolonged time delay may occur until the cutter blade reaches its ordinary rotation speed.
Japanese Utility Model Application Publication No. 54-16992 discloses a technique in which a decrease in engine rotation speed due to the increase in engine load is compensated. According to this technique, idling rotation speed is increased when the requirement for engine output is increased due to initiation of the air cooling conditioning during engine idling.
However, the conventional technique is only available in a case where relatively large load is continuously applied to the engine. Therefore, the technique is not appropriate for solving the problem attendant to the temporary increase in the load as discussed above.
It is therefore, an object of the present invention to provide a control device in a mower in which the decrease in engine rotational speed can be minimized even if the engine load is temporarily increased due to a clutch coupling, which increase in load occurs by the employment of a cutter blade for mowing, and to provide such control device capable of promptly recovering an ordinary engine rotation speed.